Elsevier

Ophthalmology

Volume 116, Issue 5, May 2009, Pages 877-881
Ophthalmology

Original article
Iris Morphologic Changes Related to α1-Adrenergic Receptor Antagonists: Implications for Intraoperative Floppy Iris Syndrome

https://doi.org/10.1016/j.ophtha.2008.12.040Get rights and content

Purpose

To identify iris structural alterations associated with intraoperative floppy iris syndrome (IFIS) in patients using systemic α1-adrenergic receptor antagonists (α-1ARA).

Design

Cross-sectional study.

Participants and Controls

Twenty-nine patients with current or past treatment with any systemic α-1ARA and 22 untreated controls.

Methods

Consecutive eligible patients underwent slit-lamp–adapted optical coherence tomography in a masked fashion under standardized lighting conditions.

Main Outcome Measures

Iris thickness at the dilator muscle region (DMR; measured at half of the distance between the scleral spur and the pupillary margin) and at the sphincter muscle region (SMR; 0.75 mm from the pupillary margin), the ratio between the DMR/SMR (to compensate for possible intersubject variability), and pupillary diameter.

Results

Most treated patients were on tamsulosin (27/29). Mean age was similar in study and control groups (70.6±7.6 vs 67.1±9.1 years; P = 0.061). Photopic pupil diameter was reduced in the study group (2.06±0.5 vs 2.5±0.6 mm; P = 0.001). The SMR was similar between groups (P = 0.53). Significantly lower values were found in treated subjects for the DMR and the DMR/SMR ratio (P<0.001). These differences remained significant after adjusting for pupil diameter (P<0.001). Multiple regression analysis showed that a longer duration of α-1ARA treatment correlated to a reduced DMR/SMR ratio (P = 0.001; r = 0.47). Age and eye color were not significant in this model.

Conclusions

Patients using systemic α-1ARA have significantly lower values of DMR thickness and DMR/SMR ratio and smaller pupil diameter when compared with age-matched controls. These differences seem to be related to the duration of drug exposure and provide evidence of structural alterations to the iris dilator muscle from this class of agents in IFIS.

Financial Disclosure(s)

Proprietary or commercial disclosure may be found after the references.

Section snippets

Patients and Methods

This noninterventional, cross-sectional study adhered to the tenets of the Declaration of Helsinki, was compliant with the Health Insurance Portability and Accountability Act, and was approved by the Institutional Review Board of The New York Eye and Ear Infirmary. Written informed consent was obtained from all subjects.

Results

Characteristics of patients in both groups are given in Table 1. Most patients in the study group were currently under treatment (22/29) and on tamsulosin (27/29). The other 2 patients were on terazosin. Patients in the study group had been treated with a systemic α-1ARA for 28.2±24.6 months. Regarding glaucoma diagnosis, there were no significant differences between study and control groups for open-angle glaucoma (34% vs. 31%), angle-closure glaucoma (38% vs. 42%), and glaucoma suspects (28%

Discussion

There is a significant difference in iris morphology in patients with a past or current history of α-1ARA use as compared with age-matched controls. Treated patients had significantly decreased DMR thicknesses, lower DMR/SMR ratios, and smaller pupillary diameters. These alterations seem to be related to the length of time of α-1ARA usage.

This is the first report demonstrating a structural alteration in the iris DMR in patients using α-1ARAs. These alterations presumably account for the

References (25)

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Manuscript no: 2008-1229.

Financial Disclosure(s): R. Ritch: Alcon (c), Allergan (c), Merck (c), Pfizer (c), Ocular Instruments (p).

J.M. Liebmann: Heidelberg (instrument support).

None of the other authors have any conflict of interest regarding the present study.

Supported in part by the Educational Foundation of America, Westport, Connecticut. Supported in part by the NIH (grant no. NIH-R01-EY1579502).

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